Wafer processing deposition shielding components

ABSTRACT

Embodiments described herein generally relate to components for a semiconductor processing chamber, a process kit for a semiconductor processing chamber, and a semiconductor processing chamber having a process kit. In one embodiment a lower shield for encircling a sputtering target and a substrate support is provided. The lower shield comprises a cylindrical outer band having a first diameter dimensioned to encircle the sputtering surface of the sputtering target and the substrate support, the cylindrical band comprising a top wall that surrounds a sputtering surface of a sputtering target and a bottom wall that surrounds the substrate support, a support ledge comprising a resting surface and extending radially outward from the cylindrical outer band, a base plate extending radially inward from the bottom wall of the cylindrical band, and a cylindrical inner band coupled with the base plate and partially surrounding a peripheral edge of the substrate support.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. patent application Ser. No.12/423,444, filed Apr. 14, 2009, which claims benefit of U.S.Provisional Patent Application Ser. No. 61/045,556, filed Apr. 16, 2008,and U.S. Provisional Patent Application Ser. No. 61/049,334, filed Apr.30, 2008, all of which are herein incorporated by reference in theirentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments described herein generally relate to components for asemiconductor processing chamber, a process kit for a semiconductorprocessing chamber, and a semiconductor processing chamber having aprocess kit. More specifically, embodiments described herein relate to aprocess kit that includes a ring assembly and multiple shields suitablefor use in a physical vapor deposition chamber.

2. Description of the Related Art

In the manufacture of integrated circuits and displays, a substrate suchas a semiconductor wafer or display panel, is placed in a substrateprocessing chamber and processing conditions are set in the chamber todeposit or etch material on the substrate. A typical process chambercomprises chamber components that include an enclosure wall thatencloses a process zone, a gas supply to provide a process gas in thechamber, a gas energizer to energize the process gas to process thesubstrate, a gas exhaust to remove spent gas and maintain a gas pressurein the chamber, and a substrate support to hold the substrate. Suchchambers can include, for example, sputtering (PVD), chemical vapordeposition (CVD), and etching chambers. In PVD chambers, a target issputtered by energized gas to sputter target material which thendeposits on the substrate facing the target.

In sputtering processes, the material sputtered from the target alsodeposits on the edges of chamber components surrounding the target whichis undesirable. The peripheral target regions have a dark-space regionin which sputtered material redeposit as a result of ion scattering inthis area. Accumulation and build-up of the sputtered material in thisregion is undesirable as such accumulated deposits require disassemblyand cleaning or replacement of the target and surrounding components,can result in plasma shorting, and can cause arcing between the targetand the chamber wall. These deposits also often debond and flake off dueto thermal stresses to fall inside and contaminate the chamber and itscomponents.

A process kit comprising a shield, cover ring and deposition ringarranged about the substrate support and chamber sidewalls, is oftenused to receive the excess sputtered material to protect and preventdeposition on the chamber walls and other component surfaces.Periodically, the process kit components are dismantled and removed fromthe chamber for cleaning off accumulated deposits. Thus it is desirableto have process kit components which are designed to receive andtolerate ever larger amounts of accumulated deposits without sticking toeach other or to the substrate, or resulting in flaking off of thedeposits between process clean cycles. It is further desirable to have aprocess kit comprising fewer parts or components, as well as havingcomponents that are shaped and arranged in relationship to one anotherto reduce the amounts of sputtered deposits formed on the internalsurfaces of the process chamber.

Another problem arises when the chamber liners and shields heat up toexcessively high temperatures due to exposure to the sputtering plasmain the chamber and poor thermal conductivity between the shield andchamber components. For example, it is difficult to control thetemperature of shields made of low thermal conductivity material. Thethermal resistances at contact interfaces with supporting components,such as adapters, also affect shield temperatures. Low clamping forcesbetween the shield and adapter can also give rise to heating up of theshield. Without thermal control, the temperature of the shields cyclesbetween idle room-temperature conditions and high temperatures duringsequential substrate processing. When process deposits of high-stressmetal are deposited onto the shields and subjected to large temperatureswings, the adhesion of the film to the shield as well as the cohesionof the film to itself, can decrease dramatically due to, for example, amismatch of the coefficients of thermal expansion between the film andthe underlying shield. It is desirable to reduce the temperatures ofshields and liners during substrate processing to reduce flaking ofaccumulated deposits from the shield surfaces.

Another problem with conventional substrate processing chamber and PVDprocesses arises due to poor gas conductance from the chamber. Ahigh-conductance gas flow pathway is needed to both supply the necessaryprocess gasses to the process cavity and to properly exhaust spentprocess gas. However, the shields and other chamber components of theprocess kit that line the chamber walls can substantially reduce gasconductance flows. Placing apertures in these components whileincreasing gas conductance therethrough, also allow line-of-sightsputtering deposits to exit the process zone through the gas conductanceholes to deposit on the chamber walls. Such holes can also cause plasmaleakage from within the processing cavity to surrounding chamberregions. Also, chamber components that incorporate such holes have othershortcomings including, but not limited to, requirement of additionalparts, their relative flimsiness, tolerance stack-ups of multiple parts,and poor thermal conductivity at interfaces.

Thus it is desirable to have process kit components that increasethermal conductivity while reducing the flaking of process deposits fromcomponent surfaces. It is further desirable to control the temperatureof the shields and liners so that they do not cycle between excessivelyhigh and low temperatures during plasma processing. It is also desirableto increase overall gas conductance while preventing line-of-sightdeposition outside the process zone and reduce plasma leakage.

SUMMARY OF THE INVENTION

Embodiments described herein generally relate to components for asemiconductor processing chamber, a process kit for a semiconductorprocessing chamber, and a semiconductor processing chamber having aprocess kit. In one embodiment a lower shield for encircling asputtering target and a substrate support is provided. The lower shieldcomprises a cylindrical outer band having a first diameter dimensionedto encircle the sputtering surface of the sputtering target and thesubstrate support, the cylindrical band comprising a top wall thatsurrounds a sputtering surface of a sputtering target and a bottom wallthat surrounds the substrate support, a support ledge comprising aresting surface and extending radially outward from the cylindricalouter band, a base plate extending radially inward from the bottom wallof the cylindrical band, and a cylindrical inner band coupled with thebase plate and partially surrounding a peripheral edge of the substratesupport.

In another embodiment, a deposition ring for encircling a peripheralwall of a substrate support in a processing chamber is provided. Thedeposition ring comprises an annular band for surrounding the peripheralwall of the substrate support, the annular band comprising an inner lipwhich extends transversely from the annular band and is substantiallyparallel to the peripheral wall of the substrate support, wherein theinner lip defines an inner perimeter of the deposition ring whichsurrounds the periphery of the substrate and substrate support toprotect regions of the support that are not covered by the substrateduring processing to reduce or even entirely preclude deposition ofsputtering deposits on the peripheral wall, and a v-shaped protuberancethat extends along a central portion of the band with a first radiallyinward recess adjacent to the inner lip and a second radially inwardrecess on either side of the v-shaped protuberance.

In yet another embodiment, a cover ring for encircling and at leastpartially shadowing a deposition ring from sputtering deposits isprovided. The deposition ring comprises an annular wedge comprising atop surface, an inclined top surface sloped radially inward and coupledwith the top surface having an inner periphery and an outer periphery, abottom surface to rest upon a ledge of a deposition ring, wherein thetop surface is substantially parallel to the bottom surface, and aprojecting brim coupled with the top surface by the inclined top surfacein cooperation with the projecting brim block line-of-sight depositionfrom exiting the interior volume and entering the chamber body cavity,and an inner cylindrical band extending downward from the annular wedge,the inner cylindrical band having a smaller height than the outercylindrical band.

In yet another embodiment a process kit for a semiconductor processingchamber is provided. The process kit comprises a lower shield, a middleshield, and a ring assembly positioned about a substrate support in aprocessing chamber to reduce deposition of process deposits on theinternal chamber components and an overhanging edge of the substrate isprovided. The lower shield comprises an outer cylindrical band having atop wall that surrounds a sputtering target and a bottom wall thatsurrounds the substrate support, a support ledge, and an innercylindrical band surrounding the substrate support. The ring assemblycomprises a deposition ring and a cover ring.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a simplified sectional view of a semiconductor processingsystem having one embodiment of a process kit described herein;

FIG. 2 is a partial sectional view of a process kit interfaced with atarget and adapter of FIG. 1;

FIG. 3A is a cross-sectional view of a lower shield according to oneembodiment described herein;

FIG. 3B is a partial sectional view of the lower shield of FIG. 3A;

FIG. 3C is a top view of the lower shield of FIG. 3A;

FIG. 4A is a cross-sectional view of a deposition ring according to oneembodiment described herein;

FIG. 4B is a partial sectional view of the deposition ring according toone embodiment described herein;

FIG. 4C is a top view of the deposition ring of FIG. 4A;

FIG. 5A is a partial section view of a middle shield according to oneembodiment described herein;

FIG. 5B is a top view of the middle shield of FIG. 5A;

FIG. 6A is a partial sectional view of a cover ring according to oneembodiment described herein;

FIG. 6B is a cross-sectional view of the cover ring of FIG. 6A; and

FIG. 6C is a top view of the cover ring of FIG. 6A.

DETAILED DESCRIPTION

Embodiments described herein generally provide a process kit for use ina physical deposition chamber (PVD) chamber. The process kit hasadvantageously provided a reduction in RF harmonics and stray plasmaoutside the process cavity, which promotes greater process uniformityand repeatability along with longer chamber component service life.

FIG. 1 depicts an exemplary semiconductor processing chamber 100 havingone embodiment of a process kit 150 capable of processing a substrate105. The process kit 150 includes a one-piece lower shield 160, aninterleaving cover ring 170, a deposition ring 180, and a middle shield190. In the embodiment shown, the processing chamber 100 comprises asputtering chamber, also called a physical deposition or PVD chamber,capable of depositing titanium, aluminum oxide, aluminum, copper,tantalum, tantalum nitride, tungsten, or tungsten nitride on asubstrate. Examples of suitable PVD chambers include the ALPS® Plus andSIP ENCORE® PVD processing chambers, both commercially available fromApplied Materials, Inc., Santa Clara, of California. It is contemplatedthat processing chambers available from other manufactures may also beutilized to perform the embodiments described herein.

The processing chamber 100 includes a chamber body 101 having enclosurewalls 102 and sidewalls 104, a bottom wall 106, and a lid assembly 108that enclose an interior volume 110 or plasma zone. The chamber body 101is typically fabricated from welded plates of stainless steel or aunitary block of aluminum. The sidewalls 104 generally contain a slitvalve (not shown) to provide for entry and egress of a substrate 105from the processing chamber 100. A pumping port 120 disposed in thesidewalls 104 is coupled to a pumping system 122 that exhausts andcontrols the pressure of the interior volume 110. The lid assembly 108of the processing chamber 100 works in cooperation with the lower shield160 that interleaves with the cover ring 170, the middle shield 190, andan upper shield 195 to confine a plasma formed in the interior volume110 to the region above the substrate.

A pedestal assembly 124 is supported from the bottom wall 106 of thechamber 100. The pedestal assembly 124 supports the deposition ring 180along with the substrate 105 during processing. The pedestal assembly124 is coupled to the bottom wall 106 of the chamber 100 by a liftmechanism 126 that is configured to move the pedestal assembly 124between an upper and lower position. Additionally, in the lowerposition, lift pins may be moved through the pedestal assembly 124 tospace the substrate 105 from the pedestal assembly 124 to facilitateexchange of the substrate 105 with a wafer transfer mechanism disposedexterior to the processing chamber 100, such as a single blade robot(not shown). A bellows 129 is typically disposed between the pedestalassembly 124 and the chamber bottom wall 106 to isolate the interiorvolume 110 of the chamber body 101 from the interior of the pedestalassembly 124 and the exterior of the chamber.

The pedestal assembly 124 generally includes a substrate support 128sealingly coupled to a platform housing 130. The platform housing 130 istypically fabricated from a metallic material such as stainless steel oraluminum. A cooling plate (not shown) is generally disposed within theplatform housing 130 to thermally regulate the substrate support 128.One pedestal assembly 124 that may be adapted to benefit from theinvention is described in U.S. Pat. No. 5,507,499, issued Apr. 16, 1996to Davenport et al., which is incorporated herein by reference in itsentirety.

The substrate support 128 may be comprised of aluminum or ceramic. Thesubstrate support 128 has a substrate receiving surface 132 thatreceives and supports the substrate 105 during processing, the substratereceiving surface 132 having a plane substantially parallel to asputtering surface 134 of a sputtering target 136. The support 128 alsohas a peripheral wall 138 that terminates before an overhanging edge 107of the substrate 105. The substrate support 128 may be an electrostaticchuck, a ceramic body, a heater or a combination thereof. In oneembodiment, the substrate support 128 is an electrostatic chuck thatincludes a dielectric body having a conductive layer embedded therein.The dielectric body is typically fabricated from a high thermalconductivity dielectric material such as pyrolytic boron nitride,aluminum nitride, silicon nitride, alumina or an equivalent material.

The lid assembly 108 generally includes the target 136 and a magnetron140. The lid assembly 108 is supported by the sidewalls 104 when in aclosed position, as shown in FIG. 1. An isolator ring 142 is disposedbetween the target 136 and the upper shield 195 to prevent vacuumleakage therebetween and reduce electrical shorts between the chamberwalls and the target 136. In one embodiment the upper shield 195comprises a material such as aluminum or stainless steel.

The target 136 is coupled to the lid assembly 108 and exposed to theinterior volume 110 of the processing chamber 100. The target 136provides material which is deposited on the substrate during a PVDprocess. The isolator ring 142 is disposed between the target 136 andchamber body 101 to electrically isolate the target 136 from the chamberbody 101. In one embodiment, the isolator ring 142 comprises a ceramicmaterial.

The target 136 and pedestal assembly 124 are biased relative to eachother by a power source 144. A gas, such as argon, is supplied to theinterior volume 110 from a gas source 146 via conduits 148. The gassource 146 may comprise a non-reactive gas such as argon or xenon, whichis capable of energetically impinging upon and sputtering material fromthe target 136. The gas source 146 may also include a reactive gas, suchas one or more of an oxygen-containing gas and a nitrogen-containinggas, that are capable of reacting with the sputtering material to form alayer on a substrate. Spent process gas and byproducts are exhaustedfrom the chamber 100 through pumping port 120 that receive spent processgas and pass the spent process gas to an exhaust conduit 121 having athrottle valve to control the pressure of the gas in the chamber 100.The exhaust conduit 148 is connected to the pumping system 122.Typically, the pressure of the sputtering gas in the chamber 100 is setto sub-atmospheric levels, such as a vacuum environment, for example,gas pressures of 1 mTorr to 400 mTorr. Plasma is formed between thesubstrate 105 and the target 136 from the gas. Ions within the plasmaare accelerated toward the target 136 and cause material to becomedislodged from the target 136. The dislodged target material isdeposited on the substrate 105.

The magnetron 140 is coupled to the lid assembly 108 on the exterior ofthe processing chamber 100. The magnetron 140 includes at least onerotating magnet assembly (not shown) that promotes uniform consumptionof the target 136 during the PVD process. One magnetron which may beutilized is described in U.S. Pat. No. 5,953,827, issued Sep. 21, 1999to Or et al., which is hereby incorporated by reference in its entirety.

The chamber 100 is controlled by a controller 196 that comprises programcode having instruction sets to operate components of the chamber 100 toprocess substrates in the chamber 100. For example, the controller 196can comprise program code that includes a substrate positioninginstruction set to operate the substrate support 128; a gas flow controlinstruction set to operate gas flow control valves to set a flow ofsputtering gas to the chamber 100; a gas pressure control instructionset to operate a throttle valve to maintain a pressure in the chamber100; a temperature control instruction set to control a temperaturecontrol system (not shown) in the support 128 or sidewall 104 to settemperatures of the substrate or sidewalls 104, respectively; and aprocess monitoring instruction set to monitor the process in the chamber100.

A collimator 197 is coupled with the lower shield 160, thereby groundingthe collimator. In one embodiment, the collimator may be a metal ringand includes an outer tubular section and at least one inner concentrictubular section, for example, three concentric tubular sections linkedby struts.

The chamber 100 also contains a process kit 150 which comprises variouscomponents that can be easily removed from the chamber 100, for example,to clean sputtering deposits off the component surfaces, replace orrepair eroded components, or to adapt the chamber 100 for otherprocesses. In one embodiment, the process kit 150 comprises a lowershield 160, a middle shield 190, and a ring assembly 202 for placementabout a peripheral wall 138 of the substrate support 128 that terminatesbefore an overhanging edge 107 of the substrate 105. As shown in FIG. 2,the ring assembly 202 comprises the deposition ring 180 and the coverring 170. The deposition ring 180 comprises an annular band 402surrounding the support 128. The cover ring 170 at least partiallycovers the deposition ring 180. The deposition ring 180 and the coverring 170 cooperate with one another to reduce formation of sputterdeposits on the peripheral wall 138 of the support 128 and theoverhanging edge 107 of the substrate 105.

The lower shield 160 encircles the sputtering surface 134 of thesputtering target 136 that faces the substrate support 128 and theperipheral wall 138 of the substrate support 128. The lower shield 160covers and shadows the sidewalls 104 of the chamber 100 to reducedeposition of sputtering deposits originating from the sputteringsurface 134 of the sputtering target 136 onto the components andsurfaces behind the lower shield 160. For example, the lower shield 160can protect the surfaces of the support 128, the overhanging edge 107 ofthe substrate 105, sidewalls 104 and bottom wall 106 of the chamber 100.

FIGS. 3A and 3B are partial sectional views of a lower shield accordingto one embodiment described herein. FIG. 3C is a top view of the lowershield of FIG. 3A. As shown in FIG. 1 and FIGS. 3A-3C, the lower shield160 is of unitary construction and comprises a cylindrical outer band310 having a diameter dimensioned to encircle the sputtering surface 134of the sputtering target 136 and the substrate support 128. Thecylindrical outer band 310 has a top wall 312 that surrounds thesputtering surface 134 of the sputtering target 136. A support ledge 313extends radially outward from the top wall 312 of the cylindrical outerband 310. The support ledge 313 comprises a resting surface 314 to restupon a first annular adapter 172 surrounding the sidewalls 104 of thechamber 100. The resting surface 314 may have a plurality of slotsshaped to receive a pin to align the lower shield 160 to the firstannular adapter 172.

As shown in FIG. 3B, the top wall 312 comprises an inner periphery 326and an outer periphery 328. The outer periphery 328 extends to form asloped step 330. The sloped step 330 is angled radially outward betweenabout 5 degrees and about 10 degrees from vertical, for example, about 8degrees from vertical. In one embodiment, the inner periphery 326 isangled radially inward between about 2 degrees and about 5 degrees, forexample, about 3.5 degrees from vertical.

The first annular adapter 172 supports the lower shield 160 and canserve as a heat exchanger about the sidewall 104 of the substrateprocessing chamber 100. The first annular adapter 172 and shield 160form an assembly that allows for better heat transfer from the shield160 to the adapter 172 and which reduces thermal expansion stresses onthe material deposited on the shield. Portions of the shield 160 canbecome excessively heated by exposure to the plasma formed in thesubstrate processing chamber, resulting in thermal expansion of theshield and causing sputtering deposits formed on the shield to flake offfrom the shield and fall upon and contaminate the substrate 105. Thefirst adapter 172 has a contact surface 174 that contacts the restingsurface 314 of the lower shield 160 to allow good thermal conductivitybetween the shield 160 and the adapter 172. In one embodiment, theresting surface 314 of the shield 160 and the contact surface 174 of thefirst adapter 172 each have a surface roughness of from about 10 toabout 80 microinches, or even from about 16 to about 63 microinches, orin one embodiment an average surface roughness of about 32 microinches.In one embodiment, the first adapter 172 further comprises conduits forflowing a heat transfer fluid therethrough to control the temperature ofthe first adapter 172.

Below the support ledge 313 of the lower shield 160 is a bottom wall 316that surrounds the substrate support 128. A base plate 318 extendsradially inward from the bottom wall 316 of the cylindrical outer band310. A cylindrical inner band 320 is coupled with the base plate 318 andat least partially surrounding the peripheral wall 138 of the substratesupport 128. The cylindrical inner band 320, the base plate 318, and thecylindrical outer band 310 form a U-shaped channel. The cylindricalinner band 320 comprises a height that is less than the height of thecylindrical outer band 310. In one embodiment, the height of the innerband 320 is about one fifth of the height of the cylindrical outer band310. In one embodiment, the bottom wall 316 has a notch 322. In oneembodiment, the cylindrical outer band 310 has a series of gas holes324.

The cylindrical outer band 310, the top wall 312, the support ledge 313,the bottom wall 316, and the inner cylindrical band 320 comprise aunitary structure. For example, in one embodiment, the entire lowershield 160 can be made from 300 series stainless steel, or in anotherembodiment, aluminum. A unitary lower shield 160 is advantageous overprior shields which included multiple components, often two or threeseparate pieces to make up the complete lower shield. For example, asingle piece shield is more thermally uniform than a multiple-componentshield, in both heating and cooling processes. For example, the singlepiece lower shield 160 has only one thermal interface to the firstadapter 172, allowing for more control over the heat exchange betweenthe shield 160 and the first adapter 172. A shield 160 with multiplecomponents makes it more difficult and laborious to remove the shieldfor cleaning. The single piece shield 160 has a continuous surfaceexposed to the sputtering deposits without interfaces or corners thatare more difficult to clean out. The single piece shield 160 also moreeffectively shields the sidewalls 104 from sputter deposition duringprocess cycles.

In one embodiment, the exposed surfaces of the lower shield 160 aretreated with CLEANCOAT™, which is commercially available from AppliedMaterials, Santa Clara, Calif. CLEANCOAT™ is a twin-wire aluminum arcspray coating that is applied to substrate processing chambercomponents, such as the lower shield 160, to reduce particle shedding ofdeposits on the lower shield 160 and thus prevent contamination of asubstrate 105 in the chamber 100. In one embodiment, the twin-wirealuminum arc spray coating on the lower shield 160 has a surfaceroughness of from about 600 to about 2300 microinches.

The lower shield 160 has exposed surfaces facing the interior volume 110in the chamber 100. In one embodiment, the exposed surfaces are beadblasted to have a surface roughness of 175±75 microinches. Thetexturized bead blasted surfaces serve to reduce particle shedding andprevent contamination within the chamber 100. The surface roughnessaverage is the mean of the absolute values of the displacements from themean line of the peaks and valleys of the roughness features along theexposed surface. The roughness average, skewness, or other propertiesmay be determined by a profilometer that passes a needle over theexposed surface and generates a trace of the fluctuations of the heightof the asperities on the surface, or by a scanning electron microscopethat uses an electron beam reflected from the surface to generate animage of the surface.

With reference to FIGS. 4A-4C, the deposition ring 180 comprises anannular band 402 that extends about and surrounds the peripheral wall138 of the support 128 as shown in FIG. 2. The annular band 402comprises an inner lip 404 which extends transversely from the band 402and is substantially parallel to the peripheral wall 138 of the support128. The inner lip 404 terminates immediately below the overhanging edge107 of the substrate 105. The inner lip 404 defines an inner perimeterof the deposition ring 180 which surrounds the periphery of thesubstrate 105 and substrate support 128 to protect regions of thesupport 128 that are not covered by the substrate 105 during processing.For example, the inner lip 404 surrounds and at least partially coversthe peripheral wall 138 of the support 128 that would otherwise beexposed to the processing environment, to reduce or even entirelypreclude deposition of sputtering deposits on the peripheral wall 138.Advantageously, the deposition ring 180 can be easily removed to cleansputtering deposits from the exposed surfaces of the ring 180 so thatthe support 128 does not have to be dismantled to be cleaned. Thedeposition ring 180 can also serve to protect the exposed side surfacesof the support 128 to reduce their erosion by the energized plasmaspecies.

In the embodiment shown in FIG. 2, the annular band 402 of thedeposition ring 180 has a v-shaped protuberance 406 that extends alongthe central portion of the band 402 with a first radially inward recess408 a and a second radially inward recess 408 b on either side of thev-shaped protuberance 406. In one embodiment, the opposing surfaces ofthe v-shaped protuberance 406 form an angle “α”. In one embodiment, theangle “α” is between about 25° and about 30°. In another embodiment, theangle “α” is between about 27° and about 28°. The first radially inwardrecess 408 a is located in a horizontal plane slightly below thehorizontal plane of the second radially inward recess 408 b. In oneembodiment, the second radially inward recess 408 b has a width betweenabout 0.8 inches and about 0.9 inches. In another embodiment, the secondradially inward recess 408 b has a width between about 0.83 inches andabout 0.84 inches. In one embodiment, the first radially inward recess408 a and the second radially inward recess 408 b are substantiallyparallel to a bottom surface 420 of the deposition ring 180. The secondradially inward recess 408 b is spaced apart from the cover ring 170 toform an arc-shaped channel 410 therebetween which acts as a labyrinth toreduce penetration of plasma species into the arc-shaped channel 410, asshown in FIG. 2. An open inner channel 412 lies between the inner lip404 and the v-shaped protuberance 406. The open inner channel 412extends radially inward to terminate at least partially below theoverhanging edge 107 of the substrate 105. The open inner channel 412facilitates the removal of sputtering deposits from these portionsduring cleaning of the deposition ring 180. The deposition ring 180 alsohas a ledge 414 which extends outward and is located radially outward ofthe V-shaped protuberance 406. The ledge 414 serves to support the coverring 170. The bottom surface 420 of the annular band 402 has a notch 422which extends from the inner lip 404 under the V-shaped protuberance406. In one embodiment, the notch has a width between about 0.6 inchesand about 0.75 inches. In another embodiment, the notch has a widthbetween about 0.65 inches and about 0.69 inches. In one embodiment, thenotch has a height between about 0.020 inches and 0.030 inches. Inanother embodiment, the notch has a height between about 0.023 inchesand about 0.026 inches.

In one embodiment, the second radially inward recess 408 b has an outerdiameter shown by arrows “A”. In one embodiment, the diameter “A” of thesecond radially inward recess 408 b may be between about 13 inches andabout 13.5 inches. In another embodiment, the diameter “A” of the secondradially inward recess 408 b may be between about 13.1 inches and about13.2 inches. In one embodiment, the second radially inward recess 408 bhas an inner diameter shown by arrows “E”. In one embodiment, thediameter “E” of the second radially inward recess 408 b may be betweenabout 12 inches and about 12.5 inches. In another embodiment, thediameter “E” may be between about 12.2 inches and 12.3 inches.

In one embodiment, the annular band 402 has a diameter as shown byarrows “D”. In one embodiment, the diameter “D” of the annular band 402may be between about 11 inches and about 12 inches. In anotherembodiment, the diameter “D” of the annular band 402 may be betweenabout 11.25 inches and about 11.75 inches. In yet another embodiment,the diameter “D” of the annular band 402 may be between about 11.40inches and about 11.60 inches. In one embodiment, the annular band 402has an outer diameter as shown by arrows “F”. In one embodiment, thediameter “F” of the annular band 402 may be between about 13 inches andabout 14 inches. In another embodiment, the diameter “F” of the annularband 402 may be between about 13.25 inches and about 13.75 inches. Inyet another embodiment, the diameter “F” may be between 13.40 inches andabout 13.60 inches.

In one embodiment the top of the v-shaped protuberance has a diametershown by arrows “B”. In one embodiment, the diameter “B” may be betweenabout 12 inches and about 12.3 inches. In another embodiment, thediameter “B” may be between about 12.1 inches and about 12.2 inches.

In one embodiment, the inner lip 404 has an outer diameter shown byarrows “C”. In one embodiment, the diameter “C” may be between about 11inches and about 12 inches. In another embodiment, the diameter “C” maybe between about 11.5 inches and about 11.9 inches. In yet anotherembodiment, the diameter “C” may be between about 11.7 inches and about11.8 inches.

The deposition ring 180 can be made by shaping and machining a ceramicmaterial, such as aluminum oxide. Preferably, the aluminum oxide has apurity of at least about 99.5 percent to reduce contamination of thechamber 100 by undesirable elements such as iron. The ceramic materialis molded and sintered using conventional techniques such as isostaticpressing, followed by machining of the molded sintered preform usingsuitable machining methods to achieve the shape and dimensions required.

The annular band 402 of the deposition ring 180 may comprise an exposedsurface that is grit blasted. Grit blasting is performed with a gritsize suitable to achieve the predefined surface roughness. In oneembodiment, a surface of the deposition ring 180 is treated with atwin-wire aluminum arc-spray coating, such as, for example, CLEANCOAT™,to reduce particle shedding and contamination.

FIG. 5A is a partial section view of a middle shield 190 according toone embodiment described herein. The middle shield 190 encircles thesputtering surface 134 of the sputtering target 136 that faces thesubstrate support 128. The middle shield 190 covers and shadows the topwall 312 of the lower shield 160 and the sidewalls 104 of the chamber100 to reduce deposition of sputtering deposits originating from thesputtering surface 134 of the sputtering target 136 onto the componentsand surfaces behind the middle shield 160.

As shown in FIG. 1 and FIG. 5A, the middle shield 160 is of unitaryconstruction and comprises a cylindrical band 510 having a firstdiameter D1 dimensioned to encircle the upper shield 195. Thecylindrical outer band 310 has a top wall 512 that surrounds the uppershield 195, a middle wall 517, and a bottom wall 518. A mounting flange514 extends radially outward from the top wall 512 of the cylindricalband 510. The mounting flange 514 comprises a resting surface 516 torest upon a second annular adapter 176 surrounding the sidewalls 104 ofthe chamber 100. The resting surface may comprise a plurality of slotsshaped to receive a pin to align the middle shield 190 to the adapter176.

The middle wall 517 is an extension of the top wall 512. The middle wall517 is sloped radially inward from the top wall 512 beginning at atransition point between the top wall 512 and the middle wall 517. Inone embodiment the middle wall 517 is angled between about 5° and about10° from vertical, for example, about 7° from vertical. The middle wall517 of the cylindrical band forms a second diameter D2. The seconddiameter D2 is dimensioned to fit within the sloped portion of the topwall 312 of the lower shield 160.

The bottom wall 518 is an extension of the middle wall 517. The bottomwall 518 is sloped radially outward relative to the middle wall 517beginning at a transition point between the middle wall 517 and thebottom wall 518. In one embodiment the bottom wall 518 is angled betweenabout 1° and about 5° from vertical, for example, about 4° fromvertical.

The top wall 512, the middle wall 517, the bottom wall 518, and themounting flange 514 comprise a unitary structure. For example, in oneembodiment, the entire middle shield 190 can be made from 300 seriesstainless steel, or in another embodiment, aluminum.

With reference to FIGS. 1, 2, 6A, 6B, and 6C, the cover ring 170encircles and at least partially covers the deposition ring 180 toreceive, and thus, shadow the deposition ring 180 from the bulk of thesputtering deposits. The cover ring 170 is fabricated from a materialthat can resist erosion by the sputtering plasma, for example, ametallic material such as stainless steel, titanium or aluminum, or aceramic material, such as aluminum oxide. In one embodiment, the coverring 170 is composed of titanium having a purity of at least about 99.9percent. In one embodiment, a surface of the cover ring 170 is treatedwith a twin-wire aluminum arc-spray coating, such as, for example,CLEANCOAT™, to reduce particle shedding from the surface of the coverring 170. The cover ring has an outer diameter shown by arrows “H”. Inone embodiment, the diameter “H” is between about 14.5 inches and about15 inches. In another embodiment, the diameter “H” is between about 14.8inches and about 14.9 inches. The cover ring has an inner diameter shownby arrows “I”. In one embodiment, the diameter “I” is between about 11.5inches and about 12.5 inches. In another embodiment, the diameter “I” isbetween about 11.8 inches and about 12.2 inches. In yet anotherembodiment, the diameter “I” is between about 11.9 inches and about 12.0inches.

The cover ring 170 comprises an annular wedge 602. The annular wedgecomprises a top surface 603 and a bottom surface 604 to rest upon theledge 414 of the deposition ring 180. The top surface 603 issubstantially parallel to the bottom surface 604. An inclined topsurface 603 couples the top surface 603 with a projecting brim 610. Theinclined top surface 605 is sloped radially inwards and encircles thesubstrate support 128. The inclined top surface 605 of the annular wedge602 has an inner and outer periphery 606, 608. The inner periphery 606comprises the projecting brim 610 which overlies the second radiallyinward recess 408 b of the deposition ring 180 forming an arc shapedchannel 410 of the deposition ring 180. The projecting brim 610 reducesdeposition of sputtering deposits on the arc shaped channel 410 of thedeposition ring 180. Advantageously, the projecting brim 610 projects adistance corresponding to at least about half the width of the openinner channel 412 formed with the deposition ring 180. The projectingbrim 610 is sized, shaped, and positioned to cooperate with andcomplement the arc-shaped channel 410 and open inner channel 412 to forma convoluted and constricted flow path between the cover ring 170 anddeposition ring 180 that inhibits the flow of process deposits onto theperipheral wall 138. The constricted flow path of the arc-shaped channel410 restricts the build-up of low-energy sputter deposits on the matingsurfaces of the deposition ring 180 and the cover ring 170, which wouldotherwise cause them to stick to one another or to the peripheraloverhanging edge of the substrate 105. The open inner channel 412 of thedeposition ring 180 which extends underneath the overhanging edge 107 ofthe substrate 105 is designed in conjunction with shadowing from theprojecting brim 610 of the cover ring 170 to collect, for example,aluminum sputter deposits in an aluminum sputtering chamber, whilereducing or even substantially precluding sputter deposition on themating surfaces of the two rings 170, 180.

The inclined top surface 605, in cooperation with the projecting brim610, block line-of-sight deposition from exiting the interior volume 110and entering the chamber body cavity. The inclined top surface 605 maybe slanted at an angle relative to the top surface 603 as shown by angle“β”. In one embodiment, the angle “β” may be between about 5 degrees andabout 15 degrees. In another embodiment, the angle “β” is between about9 degrees and about 11 degrees. In one embodiment, the angle “β” isabout 10 degrees. The angle of the inclined top surface 605 of the coverring 170 is designed, for example, to minimize the buildup of sputterdeposits nearest to the overhanging edge 107 of the substrate 105, whichwould otherwise negatively impact the deposition uniformity obtainedacross the substrate 105.

The cover ring 170 further comprises a sloped step 612 located below theinclined top surface 605 of the annular wedge 602. The sloped step 612couples the projecting brim 610 with the bottom surface 604. The slopedstep 612 extends downwardly from the annular wedge 602 and radiallyoutward from the inner periphery 606. The sloped step 612 may be slantedat an angle relative to the bottom surface as shown by angle “γ”. In oneembodiment, angle “γ” may be between about 40 degrees and about 50degrees. In another embodiment, angle “γ” may be between about 42degrees and about 48 degrees. In yet another embodiment, angle “γ” maybe between about 44 degrees and about 46 degrees.

The sloped step has an inner diameter shown by arrows “J”. In oneembodiment, the diameter “J” of the sloped step 612 is between about 12inches and about 13 inches. In another embodiment, the diameter “J” ofthe sloped step 612 is between about 12.2 and about 12.5 inches. In yetanother embodiment, the diameter “J” of the sloped step 612 is betweenabout 12.3 inches and about 12.4 inches. The sloped step 612 also has adiameter shown by arrows “K”. In one embodiment, the diameter “K” of thesloped step 612 is between about 12.5 and about 13 inches. In anotherembodiment, the diameter “K” of the sloped step 612 is between about12.7 inches and about 12.8 inches. In one embodiment, the diameter “K”of the sloped step 612 functions as the inner diameter of the bottomsurface 604.

The bottom surface has an outer diameter shown by arrows “L”. In oneembodiment, the diameter “L” of the bottom surface is between about 13.5and about 13.8 inches. In another embodiment, the diameter “L” isbetween about 13.4 inches and about 13.5 inches.

The cover ring 170 further comprises an inner cylindrical band 614 a andan outer cylindrical band 614 b that extend downwardly from the annularwedge 602, with a gap 616 therebetween. In one embodiment, the gap 616has a width between 0.5 inches and about 1 inch. In another embodiment,the gap 616 has a width between about 0.7 inches and about 0.8 inches.In one embodiment, the inner and outer cylindrical bands 614 a, 614 bare substantially vertical. The cylindrical bands 614 a, 614 b arelocated radially outward of the sloped step 612 of the wedge 602. Aninner periphery 618 of the inner cylindrical band 614 a is coupled withthe bottom surface 604. In one embodiment, the inner periphery 618 ofthe inner cylindrical band 614 a may be slanted at an angle “φ” fromvertical. In one embodiment, the angle “φ” is between about 10 degreesand about 20 degrees. In another embodiment, the angle “φ” is betweenabout 14 degrees and about 16 degrees.

The inner cylindrical band 614 a has a height that is smaller than theouter cylindrical band 614 b. Typically, the height of the outercylindrical band 614 b is at least about 2 times the height of the innercylindrical band 614 a. In one embodiment, the height of the outercylindrical band 614 b is between about 0.4 inches and about 1 inch. Inanother embodiment, the height of the outer cylindrical band 614 b isbetween 0.6 inches and 0.7 inches. In one embodiment, the height of theinner cylindrical band 614 a is between about 0.2 inches and 0.6 inches.In another embodiment, the height of the inner cylindrical band 614 a isbetween about 0.3 inches and 0.4 inches.

In one embodiment, the outer diameter “L” of the bottom surfacefunctions as the inner diameter of the inner cylindrical band 614 a. Theinner cylindrical band 614 a has an outer diameter shown by arrows “M”.In one embodiment, the diameter “M” of the inner cylindrical band 614 ais between about 13.5 inches and about 14.2 inches. In anotherembodiment, the diameter “M” of the inner cylindrical band 614 a isbetween about 13.7 and 14 inches. In yet another embodiment, thediameter “M” of the inner cylindrical band is between about 13.8 inchesand about 13.9 inches.

In one embodiment, the outer cylindrical band 614 b has an innerdiameter as shown by arrows “N”. In one embodiment, the diameter “N” isbetween about 14 inches and about 15 inches. In another embodiment, thediameter “N” of the outer cylindrical band 614 b is between about 14.2inches and about 14.8 inches. In another embodiment, the diameter “N” ofthe outer cylindrical band 614 b is between about 14.5 inches and about14.6 inches. In one embodiment, the diameter “H” of the cover ringfunctions as the outer diameter of the outer cylindrical band “H”.

In one embodiment, the cover ring 170 is adjustable and effectivelyshields conductance holes in the lower shield 160 at a range ofdifferent heights. For example, the cover ring 170 is capable of beingraised and lowered to adjust the height of the cover ring 170 inrelationship to the substrate support 128 in the chamber 100.

The space or gap between the lower shield 160 and cover ring 170 forms aconvoluted S-shaped pathway or labyrinth for plasma to travel. The shapeof the pathway is advantageous, for example, because it hinders andimpedes ingress of plasma species into this region, reducing undesirabledeposition of sputtered material.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A lower shield for encircling a sputtering target and a substratesupport in a substrate processing chamber, the processing having achamber body having a tapered inside surface, the lower shieldcomprising: a cylindrical outer band having a first diameter dimensionedto encircle the sputtering surface of the sputtering target and thesubstrate support, the cylindrical band comprising: a plurality of gasholes; a bottom wall configured to surround the substrate support, thebottom wall comprising a notch; and a top wall configured to surround asputtering surface of the sputtering target, the top wall comprising: aninner periphery facing inward and angled radially inward from verticaltowards the bottom wall; and an outer periphery facing outward, whereinthe outer periphery extends to form a sloped step and the sloped step isconfigured to engage with the tapered inside surface of the chamberbody, wherein the sloped step is angled radially outward from verticaland away from the bottom wall; a support ledge comprising a restingsurface and extending radially outward from the cylindrical outer band,the resting surface having a surface roughness of from about 10 to about80 microinches and a plurality of slots; a base plate extending radiallyinward from the bottom wall of the cylindrical band; and a cylindricalinner band coupled with the base plate and configured to partiallysurround a peripheral edge of the substrate support.
 2. The lower shieldof claim 1, wherein the sloped step is angled radially outward betweenabout 5 degrees and about 10 degrees from vertical.
 3. The lower shieldof claim 2, wherein the inner periphery is angled radially inwardbetween about 2 degrees and about 5 degrees from vertical.
 4. The lowershield of claim 1, wherein the cylindrical inner band, the base plate,and the cylindrical outer band form a U-shaped channel.
 5. The lowershield of claim 4, wherein the cylindrical inner band comprises a heightthat is less than the height of the cylindrical outer band.
 6. Theshield of claim 5, wherein the height of the cylindrical inner band isabout one fifth of the height of the cylindrical outer band.
 7. Thelower shield of claim 1, wherein the bottom wall has a notch.
 8. Thelower shield of claim 1, wherein the cylindrical outer band, the topwall, the support ledge, the bottom wall, and the inner cylindrical bandcomprise a unitary structure.
 9. The lower shield of claim 1, whereinexposed surfaces of the lower shield are bead blasted to have a surfaceroughness of 175±75 microinches.
 10. The lower shield of claim 1,further comprising a twin-wire aluminum arc spray coating on a surfaceof the lower shield wherein the twin-wire aluminum arc spray coatingcomprise a surface roughness from about 600 to about 2300 microinches.11. A lower shield for encircling a sputtering target and a substratesupport in a substrate processing chamber, the processing having achamber body having a tapered inside surface, the lower shieldcomprising: a cylindrical outer band having a first diameter dimensionedto encircle the sputtering surface of the sputtering target and thesubstrate support, the cylindrical band comprising: a plurality of gasholes; a bottom wall configured to surround the substrate support, thebottom wall comprising a notch; and a top wall configured to surround asputtering surface of the sputtering target, the top wall comprising: aninner periphery facing inward and angled radially inward between about 2degrees and about 5 degrees from vertical towards the bottom wall; andan outer periphery facing outward, wherein the outer periphery extendsto form a sloped step and the sloped step is configured to engage withthe tapered inside surface of the chamber body, wherein the sloped stepis angled radially outward between about 5 degrees and about 10 degreesfrom vertical and away from the bottom wall; a support ledge comprisinga resting surface and extending radially outward from the cylindricalouter band, the resting surface having a surface roughness of from about10 to about 80 microinches and a plurality of slots; a base plateextending radially inward from the bottom wall of the cylindrical band;and a cylindrical inner band coupled with the base plate and configuredto partially surround a peripheral edge of the substrate support,wherein the cylindrical inner band has a height that is less than aheight of the cylindrical outer band, wherein the cylindrical outerband, the top wall, the support ledge, the bottom wall, and the innercylindrical band comprise a unitary structure, and wherein exposedsurfaces of the lower shield are bead blasted to have a surfaceroughness of 175±75 microinches.
 12. The lower shield of claim 11,further comprising a twin-wire aluminum arc spray coating on a surfaceof the lower shield wherein the twin-wire aluminum arc spray coatingcomprise a surface roughness from about 600 to about 2300 microinches.13. The lower shield of claim 11, wherein the cylindrical inner band,the base plate, and the cylindrical outer band form a U-shaped channel.14. The lower shield of claim 11, wherein the bottom wall has a notch.15. The lower shield of claim 11, wherein the sloped step is angledradially outward about 8 degrees from vertical.
 16. The lower shield ofclaim 15, wherein the inner periphery is angled radially inward about3.5 degrees from vertical.
 17. The lower shield of claim 11, wherein thecylindrical inner band has a height that is one fifth of the height ofthe cylindrical outer band.